Circuit breaker housing

ABSTRACT

Disclosed is an electrical circuit breaker having an improved case construction. The case comprises three principal elements made of suitable thermoplastic and snapped together without separate fasteners or adhesive, namely, a rocker actuator, a housing, and a base. The actuator may be provided with a light and one or more of the plastic elements may be suitably colored. A removable auxiliary terminal plug is provided in the base and the terminals are retained by turned-over tabs after insertion.

United States Patent 11 1 I Harper et al.

[11] 3,749,873 14 1 July 31,1973

1 CIRCUIT BREAKER uousinc [75] inventors: George S. Harper, Cambridge;John Richard Shand, Easton, both of Md.

[7 3] Assignee: Airpax Electronics Incorporated,

Cambridge, Md.

[22] Filed: Aug. 18, 1971 [21] Appl. No.: 172,632

[52] U.S. Cl. 200/168 R, 335/202 [51] Int. Cl. H0111 9/02 [58] Field ofSearch 200/172 R,l72 A, 200/153 T, 166 CT, 168 C, 167 A, 168 R; 335/64,202

[56] References Cited UNITED STATES PATENTS 3,626,338 12/1971 Nicol etal. 335/202 3,609,268 9/1971 Sanchez 200/167 A 3,103,570

9/1963 Gibbs .1 2001172 A 3,466,413 9/1969 Sharples ZOO/168 C PrimaryExaminer-Herman J. l-lohauser 9 Assistant Examiner-William J. SmithAttorney-LeBlanc & Shut [57] ABSTRACT Disclosed is an electrical circuitbreaker having an improved case construction. The case comprises threeprincipal elements made of suitable thermoplastic and snapped togetherwithout separate fasteners or adhesive, namely, a rocker actuator, ahousing, and a base. The actuator may be provided with a light and oneor more of the plastic elements may be suitably colored. A removableauxiliary terminal plug is provided in the base and the terminals areretained by turned-over tabs after insertion. v

5 Claims, 9 Drawing Figures PATENIEDJULS H975 3'749'873 sum 1 0r 2INVENTORS. GEORGE S. HARPER J. RICHARD SHAND BY jl v'e, a f

ATTORNEYS.

'Pmmniuwm 3,749,873 4 SHEET 2 BF 2 FIG. 6 FIG] I00 -E/QB 'l 9 i 24 24 4r 1' .FIG.9 n2 fi uz INVENTORS & GEORGE s. HARPER J. RICHARD SHANDATTORNEYS.

CIRCUIT BREAKER HOUSING 1 This invention relates to electrical circuitbreakers and more particularly to an improved circuit breaker housingfor electromagnetic circuit breakers.

Electromagnetic circuit breakers have been used for many years tointerrupt and protect a variety of electrical circuits. These breakersgenerally comprise an overcurrent coil wrapped around a magnetic core,ei-

ther with or without a hydraulic time delay tube. A contact bar carryinga movable contact is actuated by a manually operated handle through acollapsible toggle to move the contact between the open and closedpositions. The toggle is conventionally provided with a trip mechanismengaged by an armature adjacent the overcurrent coil so that an overloadcurrent through the coil attracts the armature, consequentially trippingthe toggle which collapses to open the contacts automatically. Thecircuit breakers may be single pole or multiple pole devices in whichlatter case individual poles of the multipole unit are ofteninterconnected either through the handles or by an internal mechanismsuch as a comonon trip bar.

In the past, circuit breakers have been largely considered purelyutilitarian and used only as protective devices. The breakers arecustomarily made of a black electrically insulating material, such asphenolic, with little consideration being given to the breakerappearance. 1

The present invention is directed to an improved breaker constructionand more particularly 'to an improved breaker case having a morepleasing appareance so that the aesthetic qualities of the breaker areimproved when it is placed for viewing on the front panel of electricalequipment. Thebreaker canserve as a protective device, an on-off switch,and a pilot light. Through the use of an improved assembly technique andimproved case materials, it is possible to provide the case in variouscolors and color combinations for improved appearance. In addition, thenew materials make possible economies in manufacture.

The circuit breaker case is formed essentially of three separate partswhich are assembled by snapping them together without the use of rivetsor the like. The lower case section telescopes within the upper casesection and because of the resiliency of the plastic materials fromwhich the case may be made, these two sections are snapped together. Thethird principal component of the case, also made of plastic, is themanual actuator which is also snapped into the upper or front portion ofthe case. Addtional features include an optional snapin or flushmounting construction for the panel in which the circuit breaker isplaced, as well as an illuminated handle and an improved arrangement forholding a plug in the lower case section as well as an improved terminalassembly. The circuit breaker may be provided in eitherone pole ormultipole versions with single rocker actuation. Thesnap-together-assembly elirne inates the need for rivets, epoxy, or thelike, and the plastic materials used make possible improved panelappearance through the selection of appropriate colors or colorcombinations. The breaker can be used as an on-off switch, controldevice, manually reset relay, and pilot light, in addition to circuitbreaker protection.

It is therefore one object of the present invention to provide animproved electrical circuit breaker.

Another object of the present invention is to provide an improvedelectrical circuit breaker case.

and the like.

Another object of the present invention is to provide an improvedcircuit breaker construction having a novel snap-in manual actuator.

Another object of the present invention is to provide a circuit breakerhaving an improved plug and terminal mounting construction.

These and further objects and advantages of the invention will be moreapparent upon reference to the following specification, claims, andappended drawings, wherein: l

FIG. 1 is an exploded view of an electromagnetic circuit breaker caseconstructed in accordance with the present invention; i

FIG. 2 is aside view 'of the assembled case with portions broken awayfor the sake of clarity;

FIG. 3 is a partial cross section-through the circuit breaker case takenalong line 3-3 of FIG. 2;

FIG. 4 shows an electromagnetic circuit breaker having acase constructedin accordance'withFIGS. 1-3 snap-mounted into a circuit breaker panel;

FIG. 5 shows the circuit breaker of the present invention flush mountedto a circuit breaker panel;

' FIG. 6 shows a multipole or two-pole circuit breaker constructed inaccordance with the present invention;

FIG. 7 is an inside plan view showing the base-of the circuit breakercasing of the present invention provided with an auxiliary switch plug;

FIG. 8 is a cross section taken along line 8-8 of FIG. 7; and I FIG. 9is a cross section taken at right angles to that of FIG. 8 along line9-9 of FIG. 7.

Referring to the drawings, the novel circuit breaker of the presentinvention is generally indicated at 10 in FIGS. 4 and 5 and comprises acircuit breaker housing 12, shown in exploded view in FIG. 1, andcomprising three sections, namely, a lower section or base 14, an uppersection or housing 16, and a snap-in manual actuator 18. The inneroperating mechanisms of the circuit breaker are not shown and thesemaybe of conventional constructions,such as those shown by way ofexample only'in'assignee's U.S. Pat. Nos. 3,412,351;

r 3,444,488 and 3,497,838, the disclosures of which are incorporatedherein by reference.

' j Base :14 of the circuit breaker case is provided with a pair ofelectrical terminals 20 and 22 in a manner more fully described below.Base 14 is otherwise made of plastic and is formedwith four integralprojections 24, one on each side of the base. Housing 16 is similarlymoldedof plastic and includesan upper boss 26 and a collar 28 from whichdepends the hollow rectangular body 30 which forms the major portion ofthe circuit breaker casing and which houses the operating mechanism ofthe electromagnetic circuit breaker. Body 30 is provided with four smallrectangular apertures 32 located to receive the base projections 24 whenthe base 14 and housing 16 are snapped together.

Received in the top of housing 16 is a manual actuator 18 of generallyU-shaped cros section. The actuator comprises a pair of symmetricalhandles 34 and 36 forming a rocker and from which depend a pair ofspaced legs 38 and 40. Each of these legs is similarly bifurcated toprovide slots 42 which receive a toggle actuator bar 44 (FIG. 3) carriedby a toggle link 46. Each of the spaced legs 38 and 40 is also providedon its external surface with a L-shaped groove 48 adapted to slidablyreceive a corresponding one of the nubs "or projections 50 and 52projecting inwardly from the boss 26. The inner end of each groove at 54forms a semicylindrical bearing such that the actuator pivots with theend of each groove engaging one of the nubs 50 and 52. If desired, asmall light source, as indicated by the bulb 58, may be secured to asmall plastic shelf (not shown) supported by the breaker frame betweenthe legs 38 and 40 to illuminate the handle portions 34 and 36 of theactuator. Finally, body 16 is preferably provided with a pair ofintegral flexible wings 60 and 62, preferably having roughened orserrated end surfaces 64 to provide a snap-in mounting as more fullydescribed below.

During assembly, the actuator 18 is first moved in the direction of thearrow 66 in FIG. 1 so that the nubs 50 and 52 are received in theL-shaped grooves 48 and 50 formed in the outer surfaces of the actuatorlegs 38 and 40. The actuator is inserted and then rotated into theposition illustrated in FIG. 2 with the semicylindrical bearingsrotating about the semicylindrically shaped nubs 50. The operatingmechanism of the breaker (not shown) is then inserted into the housing12 so that the actuator bar 44 is received in the slots 42 in theactuator. With the bar received in the actuator leg slots, the actuatoris securely retained or restrained by the operating mechanism ofthecircuit breaker and namely the bar 44 so that it cannot be removed. Bydepressing first handle 34 and then handle 36 in FIG.2, the actuator isrocked back and forth'about the pivot axis'form'ed by the nubs 50 andactuator bar 44 is correspondingly rocked back and forth to open andclose the circuit breaker contacts. Finally, base 14 is moved upwardlyin the direction of the arrow 68 in FIG. 1 where it is telescopicallyreceived within the lower end of body 30 until the projections 24 snapinto the apertures 32 tightly locking the circuit breaker and caseassembly together. Once the elements l4, l6, and 18 in FIG. 1 have beenassembled, they cannot be readily disengaged without destroying thecircuit breaker case.

FIG. 4 shows a snap-in mounting provided by the wings 60 and 62. Thecircuit breaker is shown mounted on a circuit breaker panel 70 having arectangular aperture 72. Aperture 72 is slightly larger than the body 30of the case but is smaller than the collar 28. The circuit breaker isinserted through aperture 72 and the flexible wings 60 and 62 compressand pass through the aperture. The circuit breaker is inserted untilthecollar 28 engages circuit breaker panel 70, at which time the resilientwings 60 and 62 flex outwardly so that their roughened surfaces 64engage the rear edge of the aperture 72, tightly holding and locking thecircuit breaker to the panel.

FIG. shows a flush mounting construction in which a circuit breakerpanel 72 is apertured to receive a pair of screws 74 and 76. Thesescrews are threaded into the longer leg of a pair of L-shaped brackets78 and 80, the shorter legs engaging the back of the panel 72 and thelonger legs are clamped by the screws 74 and 76 against the underside ofthe collar 28. Again, the flexibility of the wings 60 and 62 permitinsertion of the brackets 78 and 80 beneath collar 28.

FIG. 6 shows a multipole circuit breaker constructed in accordance withthe present invention. The'circuit breaker is provided with a singlerocker actuator 18, in all respects identical to the actuator previouslydescribed. In FIG. 6, the circuit breaker is a multipole breaker and thehousing 16' is provided with six instead of-four apertures, two of whichare illustrated at 84 inv FIG. 6, which receivecorresponding projectionson the base 14'. Except for the size and number of interlockingprojections and apertures, the case illustrated in FIG. 6 is identicalto that previously described. The respective poles of the circuitbreaker mechanism are interconnected by suitably extending actuator bar44 so that it is common to the two toggle links, i.e., one for eachpole, corresponding to the toggle link 46 in FIG.

FIG. 7 is a plan view of a modified -base similar to the base 14previously described but provided with a plug 92 and auxiliary terminals94 and 96 for an auxiliary switch. The auxiliary switch adapted to bemounted in plug 92 is omitted for the sake of clarity but may be ofconventional construction, as shown byway of example only in assigneesU.S. Pat. No. 3,501,606, which is incorporated herein by reference. Alsoshown in FIG. 7 are the two spaced legs 98 and I00 of a metal frame 102on which the operating mechanism of the circuit breaker is mounted. Base90 is provided with a stationary contact 104 adapted tobe" engaged bythe movable contact of the circuit breaker mechanism and this stationarycontact 104 is electrically connected in a conventional manner toterminal 22. The other main terminal 20' is adapted to be connected tothe'overcurrent coil 'of the mechanism in a conventional manner. Each ofthese terminals, such as the tenninal 20, is stamped from flatelectrically conductive metal stock and is provided with lateralextensions approximately midway of its ends which are slotted so thatwhen the terminal has been inserted throughasuitable aperture in thebase 90, these slotted tabs integral with the terminals are turned overas at 106 and 108 to tightlylock the terminal in position so that itextends from the interior of the base outwardly for connection'to anexternal circuit to be protected. Plug 92 is removable and-is insertedinto a suitable aperture which remains whena knock-out portion of thebase 90 is removed. The plug 92 fits in the aperture 1 l0 and isprovided with a flange at its upper edge as illustrated at 112 whichextends outwardly to overlie the adjacent surface of base 90. Plug 92 isinserted into aperture 112 with the flange overlying the base andthe-flange 112 is heldin place by the legs and 98 of the'frame whichrest on top of the flange 112 as illustrated in FIG. 9. Terminals 94 and96 may be formed with turned-over portions on each side of theplug inthe manner of the terminals 20 or22 or, alternatively, terminals 94.and96 may be provided with lateral extensions or shoulders 114. and l 16,as illustrated in FIG. 9, on the outer side of the plug. The inner endsare turned over as illustrated at 118 and 120 in FIG. 8. j I

It is apparent from the above that the present invention provides animproved electromagnetic circuitbreaker and in particular an improvedcircuit breaker case which greatly increases the ease and economy ofassembly of the circuit breaker. Through the utilization of plasticmaterials exhibiting a limited amount of resilience, it is possible tosnap the base into the circuit breaker housing and through the provisionof flats on nubs 50 the actuator may be attached to the case without anyneed for rivets, adhesives, epoxy, or the like. The plastic materialsmake possible a wide variety of colors wherein each of the elements 14,16, and 18 is of either thesame or different colors to provide differentcolor combinations. in the preferred embodiment, the circuit breakercase is made of all thermoplastic materials and, by way of example only,the housing 16 and actuator 18 may be molded from a polycarbonate,identified as Lexan 141, manufactured by the General Electric Company.This provides a strong material which is available in a variety ofcolors. By way of example only, the base 14 and the corresponding bases14' and 90 are preferably formed from a high temperature distortionplastic such as polysulfone, identified as Pl700 as manufactured byUnion Carbide Corporation. It is understood that other plastic materialsmay be utilized where desired but the above'provide excep} tional colorcharacteristics in the polycarbonate in combination with a base materialthat has a higher temperature distortion point in the electrical contactarea.

By providing a snap-in actuator 'l 18 with the spaced legs, it ispossible to mount an incandescent or neon bulb 58 between the movinglegs of the actuator handle. This provide full handle illuminationwithout bulb movement and the associated problems of wire flexing. Whilethe plug 92 has been described in conjunction with the use of anauxiliary switch, it is understood that the plug may be used in anysituation in which two additional terminals are required. The plug isretained solely by the bottom of the circuit breaker base and the frame102. The terminals are held into the circuit breaker base by the tabsillustrated which are folded over after terminal insertion.

Theactuator 18 is inserted into housing 16 with the nubs 50 passingthrough the L-shaped slot 48 to the slot ends 54. This insertion is madepossible by providing a small flat 122 on each of the otherwisecylindrical nubs 50 and 52 so that they may be readily inserted into theends of the grooves 48. After the actuator has been lowered and rotatedinto the operating position illustrated in FIG. 2,'it is locked into thehousing 16 by re- J therefore intended to be .embraced therein.

ceipt of the actuator bar 44 into the slots 42 and excessive rotationalmotion of the actuator 18 is prevented by the bar 44 and the operatingmechanism of the circuit breaker toggle.

The invention may be embodied in other specific forms without departingfrom the spirit or essential characteristics thereof. The presentembodiments are therefore to be considered in all respects asillustrative and not restrictive, the scope of the invention beingindicated by the appended claims rather than by the foregoingdescription, and all changes which come within the meaning and range ofequivalency of the claims are What is claimed and desired to be'se'curedby Un' States Letters Patent is:

1. In an electromagnetic circuit breaker, a case comprising athermoplastic housing, a thermoplastic base, resilient fastening meanson said base and said housing joining them together, a toggle bar insaid case, and a rocker actuator pivoted to said housing, said actuatorhaving inner ends engaging said toggle bar, said base being providedwith a pair of main terminals and an aperture between. said terminals,and a plug extending throughsaid aperture and having a flange overlyingthe inner surface of said base.

2. A circuit breaker according to claim 1 including a frame in saidcase, said plug flange being clamped between said frame and the interiorsurface-of said base.

3. In an electromagnetic circuit breaker, a case comprising athermoplastic housing, a thermoplastic base,

' a resilient fastening means on said base and housing joining themtogether, a toggle bar in said case, a rocker actuator pivoted to saidhousing, said actuator having its inner end engaging said toggle bar,said actuator comprising a pair of handle portions joined to a pair ofspaced legs, the ends of said legs having slots receiving saidtoggle'bar, and including a pair of projections on said housing, saidactuator including L-shaped grooves slidably receiving said projections.

4. A circuit breaker according to claim 3 wherei said projections aresemicylindrical with flats on one side.

-5. Acircuit breaker according to claim 3 wherein said grooves havefirst portions extending from said housing projections toward saidslots, and second per-. pendicular portions terminating at a side edgeof said legs.

1. In an electromagnetic circuit breaker, a case comprising athermoplastic housing, a thermoplastic base, resilient fastening meanson said base and said housing joining them together, a toggle bar insaid case, and a rocker actuator pivoted to said housing, said actuatorhaving inner ends engaging said toggle bar, said base being providedwith a pair of main terminals and an aperture between said terminals,and a plug extending through said aperture and having a flange overlyingthe inner surface of said base.
 2. A circuit breaker according to claim1 including a frame in said case, said plug flange being clamped betweensaid frame and the interior surface of said base.
 3. In anelectromagnetic circuit breaker, a case comprising a thermoplastichousing, a thermoplastic base, a resilient fastening means on said baseand housing joining them together, a toggle bar in said case, a rockeractuator pivoted to said housing, said actuator having its inner endengaging said toggle bar, said actuator comprising a pair of handleportions joined to a pair of spaced legs, the ends of said legs havingslots receiving said toggle bar, and including a pair of projections onsaid housing, said actuator including L-shaped grooves slidablyreceiving said projections.
 4. A circuit breaker according to claim 3wherein said projections are semicylindrical with flats on one side. 5.A circuit breaker according to claim 3 wherein said grooves have firstportions extending fRom said housing projections toward said slots, andsecond perpendicular portions terminating at a side edge of said legs.